1,721,010 research outputs found
TSCH protocol scheduler
No full textDarbā tiek apskatīti TSCH protokols un to plānotāji teorētiski un praktiski. Teorētiskā daļā tiek aprakstīts, kā darbojas protokola laika sloti un kā protokols pārvalda tīklu. Praktiskā daļā tiek apskatīti dažādi tīklu veidi ar vairākiem parametriem, iegūta rezultāta pamatojums un secinājumi. Bakalaura darba tēma “TSCH protokola plānotājs” tiek izvēlēta pēc autora ieinteresētības un studiju datorinženierijas virziena izvēles. Tēmu piedāvāja darba vadītājs.The TSCH protocol and its schedulers are reviewed from the theoretical and practical aspects. The theoretical part describes how the protocol time slots work and how the protocol manages the network. In the practical part, different types of networks with several parameters are described and tested, obtained result justification and conclusions. Bachelor work theme “TSCH protocol scheduler” is chosen by author interest and by the choice of computer engineering study direction. Theme was offered by supervisor
Ietvars bezvadu sensoru tīklu lietojumprogrammu izstrādes atvieglošanai
No full textElektroniskā versija nesatur pielikumusSākotnējā vīzija par bezvadu sensoru tīkliem paredzēja, ka tie kļūs par vērtīgu rīku daudzām lietotāju grupām: gan dažādu jomu zinātniekiem, gan praktiķiem. Taču bezvadu sensoru tīklu
programmatūras izstrāde ir sarežģīta, jo tie apvieno
resursierobežotu iegulto ierīču sarežģītību ar tīklotu ierīču sarežģītību. Tas ir viens no iemesliem, kāpēc sensoru tīkli vēl nav kļuvuši par plaša patēriņa tehnoloģiju.
Šī problēma ir daļēji risināma, piedāvājot bezvadu sensoru tīklu programmatūras izstrādātājiem piemērotus programmizstrādes
rīkus, programmēšanas valodas un bibliotēkas. Tāpēc disertācijas ietvaros ir izveidota rinda pieeju bezvadu sensoru tīklu lietojumprogrammu izstrādes atvieglošanai, ieskaitot: jaunu lietojumprogrammu izstrādes valodu, kura ļauj lietojumprogrammas definēt īsākā un mazāk sarežģītā veidā, un pieeju sensoru tīklu operētājsistēmu resursefektivitātes palielināšanai. Šīs pieejas ir integrētas vienotā programmatūras ietvarā, kopā ar citu autora un viņa pētniecības grupas izstrādāto programmatūru.
Ietvars ir paredzēts divām lietotāju grupām: pirmkārt,
iesācējiem programmētājiem, otrkārt, profesionāliem
programmētājiem, tai skaitā arī tiem, kuriem ir tikai neliela pieredze bezvadu sensoru tīklos.
Veiktie eksperimenti rāda, ka piedāvātās pieejas ļauj iegūt lietojumprogrammas ar mazāku resursu patēriņu un zemāku koda sarežģītību.Wireless sensor networks is a technology that was originally envisioned as a tool for broad range of purposes and target audiences. However, wireless sensor network software development is complicated, because it brings together the complexity of resource-constrained embedded system software
and the complexity of distributed system software. This is one of the reasons why sensor networks have not yet become an ubiquitous technology.
This problem is partially solvable by decreasing the
accidental software development complexity that is at the moment present in the process of sensor network application development. The sensor network application developer must be provided with
appropriate development tools, languages and libraries in order to allow him to focus on the essential complexity of software development. Therefore this dissertation presents a number of
approaches that facilitate sensor network application
programming, including: a new application development language that allows to write applications in more concise and less complex way, and an approach to increase the resource-efficiency of sensor network operating systems. The approaches are integrated in a unified framework, along with other software designed by the
author and his research group.
This framework is targeted towards two categories of users: firstly, novice programmers, secondly, professional programmers, including programmers with limited experience in wireless sensor
networks. The evaluation shows that these approaches lead to applications with decreased resource usage and lower code complexity
Source-Node Selection to Increase the Reliability of Sensor Networks for Building Automation [Elektronisk resurs]
No full textWe experimentally investigate the performance of IEEE 802.15.4 radio links and their failure modes in an office building, and, based on this study, propose an adaptation mechanism to conciliate application-level reliability requirements with the underlying network-level properties. The mechanism has two aspects: the spatially-adaptive aspect, implemented through adaptively selecting one or more source nodes for each application-level data connection, and the frequency-adaptive aspect, implemented through IEEE 802.15.4 channel hopping and blacklisting. Through extensive trace-based simulations and experiments in a test network, we show that the mechanism satisfies application requirements on maximal information age as long as at least one of the potential source nodes is connected to the rest of the network, at the same time showing lower energy consumption than non-adaptively using multiple source nodes.</p
Source-Node Selection to Increase the Reliability of Sensor Networks for Building Automation
No full textWe experimentally investigate the performance of IEEE 802.15.4 radio links and their failure modes in an office building, and, based on this study, propose an adaptation mechanism to conciliate application-level reliability requirements with the underlying network-level properties. The mechanism has two aspects: the spatially-adaptive aspect, implemented through adaptively selecting one or more source nodes for each application-level data connection, and the frequency-adaptive aspect, implemented through IEEE 802.15.4 channel hopping and blacklisting.Through extensive trace-based simulations and experiments in a test network, we show that the mechanism satisfies application requirements on maximal information age as long as at least one of the potential source nodes is connected to the rest of the network, at the same time showing lower energy consumption than non-adaptively using multiple source nodes
Source-Node Selection to Increase the Reliability of Sensor Networks for Building Automation
Full text linkWe experimentally investigate the performance of IEEE 802.15.4 radio links and their failure modes in an office building, and, based on this study, propose an adaptation mechanism to conciliate application-level reliability requirements with the underlying network-level properties.
The mechanism has two aspects: the spatially-adaptive aspect, implemented through adaptively selecting one or more
source nodes for each application-level data connection, and
the frequency-adaptive aspect, implemented through IEEE
802.15.4 channel hopping and blacklisting.
Through extensive trace-based simulations and experiments in a test network, we show that the mechanism satisfies application requirements on maximal information age as long as at least one of the potential source nodes is connected to the rest of the network, at the same time showing lower energy consumption than non-adaptively using multiple source nodes
Symmetry detection algorithms and their applications for protein structures
No full textBakalaura darbs ir veltīts simetrijas noteikšanas algoritmu pētīšanai. Simetrija spēlē ievērojamu jomu dabā, mākslā un matemātikā. Līdz ar datortehnoloģijas attīstību ir izveidotas dažādas metodes tās automātiskai noteikšanai. Bakalaura darba praktiskais mērķis ir atrast simetrijas
noteikšanas algoritmus, kas būtu piemēroti lietošanai proteīnu molekulām. Tāda specifika liek fokusēties uz metodēm, kas meklē rotācijas simetrijas punktu kopai trīsdimensiju telpā.
Darbā apskatīti vairāki simetrijas noteikšanas algoritmi: algoritms, kas nosaka grafa automorfismus un tās izmanto kā simetrijas hipotēzes; algoritms, kas izmanto paplašināto Gausa attēlu; algoritms simetrijas novērtēšanai un frekvences noteikšanai ar Furjē transformāciju.The topic of this bachelor thesis is study of symmetry detection algorithms. Symmetry plays important role in nature, art and mathematics. With the development of computational technology several methods for its automatic detection have been developed. The practical objective of this bachelor thesis is to find algorithms suitable for application to protein molecules. We shall focus on methods that detects rotational symmetries for three dimensional point sets.
Several symmetry detection algorithms are reviewed in this paper: an algorithm that detects authomorphisms of a graph and uses them as symmetry hypotheses; an algorithm that uses Extended Gaussian Image; an algorithm for symmetry evaluation and frequency determination with Fourier transform
Visual wireless sensor network programming environment
No full textViens no lielākajiem bezvadu sensoru tīklu attīstības traucēkļiem ir nozares specifiskums un sarežģītība. Šajā darbā ir izstrādāta vizuāla bezvadu sensoru tīklu programmēšanas vide, kas ļauj lietotājiem bez īpašām zināšanām par bezvadu sensoru tīkliem veidot un augšupielādēt bezvadu sensoru tīklu lietotnes. Izveidotās vizuālas bezvadu sensoru tīklu programmēšanas vides funkcijās vairāku ciļņu atbalsta nodrošināšana, ērtas kompilēšanas un augšupielādēšanas nodrošināšana, sintakses pārbaude reālā laikā, vizuālas komandu ievades nodrošināšana, u.c. Vizuālā bezvadu sensoru tīklu programmēšanas vide ir veidota uz MansOS operētājsistēmas bāzes un kalpo par vizuālo abstrakcijas slāni MansOS iebūvētajai skriptēšanas valodai SEAL. Darba ietvaros SEAL valodas funkcionalitāte tika papildināta ar datu apstrādes iespējām.One of the greatest nuisance of wireless sensor network evolution is it’s industry specify and complexity. This work presents design and implementation of visual wireless sensor network programming environment, which allows users without knowledge about wireless sensor networks to create and upload wireless sensor network applications. Developed visual wireless sensor network programming environment features support for multiple tabs, comfortable compiling and uploading, syntax checking in real-time, support for visual command input, etc. Visual wireless sensor network programming environment is developed on basis of MansOS operating system and serves as an abstraction layer for MansOS built in scripting language called SEAL. Within this work functionality of SEAL language was updated with data processing capabilities
Optimal Task Allocation in Sensor and Actuator Networks
No full textSensor and actuator network macroprogramming techniques that use task graphs are promising options for high-level application development in this domain. However, setting up a multitude of application-level tasks in the network and subsequently keeping track of them is a nontrivial undertaking. Therefore, tool support for automated task allocation is required. Such a support is typically implemented by providing an objective function that evaluates the cost of a task mapping, and a search algorithm that attempts to minimize this function.The current algorithms for task allocation in sensor and actuator networks either do not guarantee optimal results, or are conceptually tied to a single specific objective function. Our work contributes to this state-of-art in two aspects: firstly, by finding a model that can easily accommodate several different objective functions, and secondly, by finding a search strategy that makes it feasible to allocate realistic task graphs even in large networks.</p
Concentrated Liquidity with Leverage
Full text linkConcentrated liquidity (CL) provisioning is a way how to improve the capital efficiency of Automated Market Makers (AMM). Allowing liquidity providers to use leverage is a step towards even higher capital efficiency. A number of Decentralized Finance (DeFi) protocols implement this technique in conjunction with overcollateralized lending. However, the properties of leveraged CL positions have not been formalized and are poorly understood in practice. This article describes the principles of a leveraged CL provisioning protocol, formally models the notions of margin level, assets, and debt, and proves that within this model, leveraged LP positions possess several properties that make them safe to use
Competition : Adaptive Time-Slotted Channel Hopping
No full textTime-Slotted Channel Hopping (TSCH) from the IEEE 802.15.4-2015 standard uses channel hopping to combat interference and frequency-selective fading. It has attracted large attention from the research community due to its properties: high reliability in terms of packet delivery rates, and increased predictability in terms of energy consumption and latency, as compared to commonly used low-power CSMA MAC protocols. This work makes use of the Contiki OS implementation of the TSCH protocol. We extend the standardized TSCH protocol with adaptive channel selection, adaptive time synchronization, and adaptive guard time selection to improve its energy efficiency and reliability properties
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